What are fake pearls called?

As a keen observer of the intricate world of cryptocurrency and finance, I often come across various analogies and comparisons to describe the nuances of this dynamic field. Today, my curiosity is piqued by a seemingly unrelated question: What are fake pearls called? This query, though seemingly mundane, strikes me as an apt metaphor for the counterfeit currencies and fraudulent schemes that sometimes infiltrate the crypto world. Could it be that these imitation pearls, also known as "imitation pearls" or "simulated pearls," serve as a cautionary tale for investors to be vigilant in discerning the genuine from the spurious in the vast ocean of cryptocurrencies?